A wave generator flexible support structure for a rudder harmonic reducer

Abstract

The application discloses a wave generator flexible support structure of a rudder motor harmonic reducer, which comprises a flexible wheel output assembly and a wave generator assembly sleeved on the flexible wheel output assembly, wherein the diameter d of an output shaft at a wave generator assembly support position on the flexible wheel output assembly is D-(2-4)*delta; when the diameter of the output shaft at the wave generator assembly support position on the flexible wheel output assembly is greater than or equal to 10 mm, an annular groove is arranged at the center of the support position, and a rubber O-shaped sealing ring is arranged in the annular groove. A gap is kept between the output shaft and the wave generator, and the O-shaped sealing ring is in flexible contact, so that even if the output shaft is bent and deformed, the output shaft and the wave generator do not come into rigid contact, the bending deformation does not generate additional force on the wave generator, the flexible operation of the wave generator is ensured, and the rudder motor can normally work. The annular groove is arranged, the rigidity of the output shaft is weakened, the stress condition of a small bearing is greatly reduced, and the radial load of the small bearing can be reduced by 50%-70%. Under the same volume, weight and motor power, the bending moment bearing capacity is increased by 2-3 times.

Description

Technical Field

[0001] This invention relates to a flexible support structure for the wave generator of a servo motor harmonic reducer, belonging to the technical field of servo motor harmonic reducers. Background Technology

[0002] Servo motors are the terminal actuators in the guidance systems of missiles, rockets, drones, and other aircraft. They receive commands from the flight control system or host computer and accurately and rapidly drive the control surfaces to deflect, changing the aerodynamic torque acting on the control surfaces to stabilize themselves and correct their trajectory to hit the target. Today, with the rapid development of modern warfare and the fast-changing tactics, equipment not only possesses supersonic cruise, superior stealth, and super-maneuverability capabilities, but also autonomous trajectory planning capabilities. This places higher demands on the dynamic response and load-bearing capacity of servo motors, especially during ultra-high-speed, high-angle turns, where the motors not only need to maintain high output torque but also need to withstand extremely high shear bending moment loads.

[0003] Servo motors consist of a motor, reducer, sensor, and controller. The reducer is typically a harmonic reducer, with a structure where the high-speed stage uses bevel gear transmission for 90° steering, and the low-speed stage uses harmonic gear transmission for high-precision output. Under extreme shear moment loads, the output shaft of the harmonic reducer undergoes significant bending deformation. The wave generator will then bear additional radial compressive loads, increasing the operating resistance of the wave generator (large bevel gear). This can prevent the motor from driving the reducer properly, ultimately leading to mechanism failure or even mission failure.

[0004] To improve the bending moment resistance of servo motors, the support rigidity of the output shaft is typically enhanced, and multiple bearings are installed outside the reducer to resist bending moments. For example, CN102765475A discloses an aircraft and its high bending moment resistant electric servo motor. This approach increases the size and weight of the servo motor, failing to meet the requirements for lightweighting and miniaturization. Summary of the Invention

[0005] The purpose of this invention is to provide a flexible support structure for the wave generator of a servo motor harmonic reducer. This invention eliminates the additional radial compressive load on the wave generator caused by the bending deformation of the output shaft under shear moment, ensuring flexible operation of the wave generator and normal operation of the reducer. Under the same volume, weight, and motor power, the bending moment bearing capacity is increased by 2-3 times, significantly improving the load-bearing capacity and reliability of the servo motor.

[0006] The technical solution of the present invention: A flexible support structure for a wave generator of a servo motor harmonic reducer, comprising a flexible wheel output assembly and a wave generator assembly sleeved thereon, wherein the output shaft diameter d of the wave generator assembly support position on the flexible wheel output assembly is d = D - (2~4) * δ, where D is the inner ring diameter of the central bearing of the wave generator assembly, and δ is the maximum bending deformation of the output shaft of the flexible wheel output assembly under bending moment.

[0007] The servo wave reducer includes a housing with a front cover connected to the front end of the housing, forming an installation chamber. A flexible output assembly is installed in the installation chamber. A wave generator assembly, a spacer, and a small bearing are sequentially sleeved on the output shaft of the flexible output assembly from right to left. A small bevel gear motor assembly is installed on the housing. The small bevel gear of the small bevel gear motor assembly extends into the installation chamber and meshes with the large bevel gear on the wave generator assembly.

[0008] The wave generator assembly includes a central bearing, on which a large bevel gear is sleeved. The outer contour of the boss on one side of the back cone of the large bevel gear is an elliptical cam. A flexible bearing is sleeved on the elliptical cam. A baffle is provided on the outside of the central bearing and is fixed to the large bevel gear by screws.

[0009] In the aforementioned flexible support structure for the wave generator of a servo motor harmonic reducer, when the output shaft diameter of the wave generator assembly support position on the flexible wheel output assembly is ≥10mm, an annular groove is provided at the center of the support position, and a rubber O-ring is provided in the annular groove.

[0010] In the aforementioned flexible support structure for the wave generator of a servo motor harmonic reducer, the width of the annular groove is a = (1.2~1.5)*d0, and the radial compression of the assembled rubber O-ring is k = d0-h = (0.1~0.2)*d0, where d0 is the wire diameter of the rubber O-ring and h is the groove depth of the annular groove.

[0011] In the aforementioned flexible support structure for the wave generator of a servo motor harmonic reducer, the width b of the support position of the wave generator assembly on the flexible wheel output assembly is (1.1~1.2)*B, where B is the inner ring width of the central bearing of the wave generator assembly.

[0012] The beneficial effects of this invention are as follows: Compared with the prior art, the benefits of using a flexible support structure for wave generators are manifested in the following aspects:

[0013] 1) A gap is maintained between the output shaft and the wave generator, and the elastic element (O-ring seal) makes flexible contact. Even if the output shaft is bent and deformed, the output shaft and the wave generator will not make rigid contact. The bending deformation has no additional force on the wave generator, ensuring that the wave generator operates flexibly and the servo motor works normally.

[0014] 2) The annular groove weakens the rigidity of the output shaft and greatly reduces the stress on the small bearing, which can reduce the radial load on the small bearing by 50%-70%.

[0015] 3) Under the same volume, weight and motor power, the bending moment bearing capacity is increased by 2-3 times.

[0016] In summary, the present invention adopts the above-mentioned solution, and through theoretical calculation and engineering verification, under the same volume, weight and motor power, the bending moment bearing capacity is increased by 2-3 times, and the radial load of small bearings can be reduced by 50%-70%. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the invention.

[0018] Figure 2 A simplified diagram of the transmission mechanism of a servo motor harmonic reducer;

[0019] Figure 3 This is an exploded view of the servo motor harmonic reducer of the present invention;

[0020] Figure 4 This is an assembly diagram of the servo motor harmonic reducer of the present invention;

[0021] Figure 5 This is a schematic diagram of the output shaft of the flexible gear output assembly;

[0022] Figure 6 This is an assembly diagram of the wave generator components.

[0023] Reference numerals: 1. Fastener, 2. Front end cover, 3. Flexible output assembly, 4. Rubber O-ring seal, 5. Wave generator assembly, 5-1. Flexible bearing, 5-2. Baffle, 5-3. Central bearing, 5-4. Screw, 5-5. Large bevel gear, 5-5.1. Elliptical cam, 6. Spacer, 7. Small bearing, 8. Housing, 9. Small bevel gear motor assembly, 10. Annular groove. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0025] An embodiment of the present invention: A flexible support structure for a wave generator of a servo motor harmonic reducer includes a flexible wheel output assembly 3 and a wave generator assembly 5 sleeved on the output shaft of the flexible wheel output assembly 3. The output shaft diameter d of the wave generator assembly 5 at the support position on the output shaft of the flexible wheel output assembly 3 is d = D - (2~4) * δ, where D is the inner ring diameter of the central bearing 5-3 of the wave generator assembly 5, the output shaft of the flexible wheel output assembly 3 passes through the central bearing 5-3, and δ is the maximum bending deformation of the output shaft of the flexible wheel output assembly 3 under bending moment.

[0026] Depend on Figure 2 It is known that the output shaft of a harmonic reducer for a servo motor is generally supported by two ball bearings, one at the front and one at the back. Under the action of an external shear moment load M, the output shaft undergoes bending deformation with the two bearings as fulcrums.

[0027] The bending radial deformation δ of the flexible wheel output component 3 at the support position of the wave generator component 5 is obtained by simulation or theoretical calculation. The bending radial deformation δ is obtained by reducing the diameter d of the output shaft at the support position of the wave generator component 5 on the output shaft of the flexible wheel output component 3 by (2 to 4) times.

[0028] During operation, the wave generator assembly 5 rotates around the center of the flexible wheel by relying on the cooperation between the flexible wheel on the flexible wheel output assembly 3 and the flexible bearing 3-1. When the output bearing of the flexible wheel output assembly 3 is subjected to shear bending moment and deforms, since the radial clearance between the wave generator assembly 5 and the output shaft support position is greater than the radial deformation of the output shaft, the bending deformation has no additional effect on the wave generator assembly 5, ensuring that the bending deformation of the output shaft has no effect on the support of the wave generator assembly 5.

[0029] For the output shaft diameter of the wave generator assembly 5 support position on the flexible wheel output assembly 3 that is greater than or equal to 10mm, an annular groove 10 is provided at the center of the support position on the wave generator assembly 5 on the output shaft, and a rubber O-ring seal 4 is provided in the annular groove 10. Since the annular groove 10 is provided on the output shaft of the flexible wheel output assembly 3, the rigidity of the output shaft is weakened, and the stress condition of the small bearing 7 supporting the end of the output shaft is effectively reduced.

[0030] The width of the annular groove 10 is a = (1.2~1.5)*d0, and the radial compression of the assembled rubber O-ring 4 is k = d0-h = (0.1~0.2)*d0, where d0 is the wire diameter of the rubber O-ring 4 and h is the groove depth of the annular groove 10. The wave generator assembly 5 is flexibly supported by the elastic deformation of the rubber O-ring 4.

[0031] Taking the cup-type flexible gear structure as an example, the applicability of other types of servo motor harmonic reducers cannot be ruled out.

[0032] The servo motor harmonic reducer mainly consists of fastener 1, front cover 2, flexible gear output shaft assembly 3, rubber O-ring seal 4, wave generator 5, spacer 6, small bearing 7, housing 8, and small bevel gear motor assembly 9. The front cover 2 is fixed to the front face of the housing 8 by fastener 1, forming an installation chamber. The flexible gear output assembly 3 is installed in the installation chamber. The wave generator assembly 5, spacer 6, and small bearing 7 are sequentially fitted onto the output shaft of the flexible gear output assembly 3 from right to left. The small bevel gear motor assembly 9 is installed on the housing 8. The small bevel gear of the small bevel gear motor assembly 9 extends into the installation chamber and meshes with the large bevel gear 5-5 on the wave generator assembly 5. The rubber O-ring seal 4 is installed in the annular groove 10 of the flexible gear output shaft assembly 3. The flexible gear output shaft assembly 3 consists of a flexible gear and an output shaft, as shown... Figure 3 As shown, the flexible wheel is fixed to the output shaft by screws, and two bearings are sleeved side by side on the left side of the output shaft.

[0033] The wave generator assembly 5 consists of a baffle 5-2, a large bevel gear 5-5, a flexible bearing 5-1, a central bearing 5-3, and screws 5-4. The large bevel gear 5-5 is sleeved on the central bearing 5-3. The outer contour of the boss on the back cone side of the bevel gear 5-5 is an elliptical cam 5-5.1. The flexible bearing 5-1 is sleeved on the elliptical cam 5-5.1. A baffle 5-2 is located on the outer side of the central bearing 5-3, and the baffle 5-2 is fixed to the large bevel gear 5-5 by screws 5-4. Figure 1 and Figure 4 It can be seen that the wave generator assembly 5 is sleeved on the output shaft of the flexible wheel output shaft assembly 3. Specifically, the central bearing 5-3 is sleeved on the output shaft, while the outer ring of the flexible bearing 5-1 is engaged with the annular inner wall of the flexible wheel of the flexible wheel output shaft assembly 3.

[0034] The structure of the servo motor harmonic reducer and the structure of wave generator component 5 are existing technologies, and their specific structures will not be described in detail here.

[0035] The inner ring diameter of the central bearing 5-3 of the wave generator assembly 5 is D, and the width is B. The diameter of the corresponding mounting position of the wave generator assembly 5 on the output shaft is d, and the width is b. An annular groove 10 is provided, with a groove width of a and a groove depth of h. The wire diameter of the rubber O-ring seal 4 is selected as d0. The maximum bending deformation of the output shaft of the flexible wheel output shaft assembly 3 under bending moment is δ. The compression of the rubber O-ring seal 4 is K. The dimensional parameters of the flexible support structure are designed as follows:

[0036] d = D - (2 ~ 4) * δ;

[0037] b = (1.1~1.2)*B;

[0038] K = d0 - h = (0.1 ~ 0.2) * d0;

[0039] a = (1.2 ~ 1.5) * d0.

[0040] In addition, the output shaft of the flexible gear output shaft assembly 3 is supported by two bearings (such as front and rear bearings). Figure 4 As shown, the left end of the output shaft is supported in the front cover 2 by two bearings arranged side by side, while the right end of the output shaft is supported in the housing 8 by a small bearing 7. Under bending moment, the small bearing 7 resists deformation and bears a large radial force. After the annular groove 10 is set, the rigidity of the output shaft is weakened, which greatly reduces the stress on the small bearing 7.

[0041] Using the above scheme, theoretical calculations and engineering verification show that, under the same volume, weight and motor power, the bending moment bearing capacity is increased by 2-3 times, and the radial load of small bearings can be reduced by 50%-70%.

Claims

1. A flexible support structure for a wave generator of a servo motor harmonic reducer, comprising a flexible output assembly (3) and a wave generator assembly (5) sleeved thereon, characterized in that: The output shaft diameter d of the wave generator assembly (5) at the support position of the flexible wheel output assembly (3) is d = D - (2 ~ 4) * δ, where D is the inner ring diameter of the central bearing (5-3) of the wave generator assembly (5), and δ is the maximum bending deformation of the output shaft of the flexible wheel output assembly (3) under bending moment. The width b of the support position of the wave generator assembly (5) on the flexible output assembly (3) is (1.1~1.2)*B, where B is the inner ring width of the central bearing (5-3) of the wave generator assembly (5); The servo motor harmonic reducer includes a housing (8), with a front cover (2) connected to the front end of the housing (8), and the two forming an installation chamber. A flexible output assembly (3) is installed in the installation chamber. A wave generator assembly (5), a spacer (6), and a small bearing (7) are sequentially sleeved on the output shaft of the flexible output assembly (3) from right to left. A small bevel gear motor assembly (9) is installed on the housing (8). The small bevel gear of the small bevel gear motor assembly (9) extends into the installation chamber and meshes with the large bevel gear (5-5) on the wave generator assembly (5). The wave generator assembly (5) includes a central bearing (5-3), a large bevel gear (5-5) is sleeved on the central bearing (5-3), the outer circle of the boss on the back cone side of the large bevel gear (5-5) is an elliptical cam (5-5.1), a flexible bearing (5-1) is sleeved on the elliptical cam (5-5.1), and a baffle (5-2) is provided on the outside of the central bearing (5-3), and the baffle (5-2) is fixed on the large bevel gear (5-5) by screws (5-4).

2. The flexible support structure for the wave generator of a servo motor harmonic reducer according to claim 1, characterized in that: When the output shaft diameter of the upper wave generator assembly (5) of the flexible wheel output assembly (3) is ≥10mm, an annular groove (10) is provided at the center of the support position, and a rubber O-ring (4) is provided in the annular groove (10).

3. The flexible support structure for the wave generator of a servo motor harmonic reducer according to claim 2, characterized in that: The width of the annular groove (10) is a = (1.2~1.5)*d0, and the radial compression of the assembled rubber O-ring (4) is k = d0-h = (0.1~0.2)*d0, where d0 is the wire diameter of the rubber O-ring (4) and h is the groove depth of the annular groove (10).

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